From a Ubuntu perspective I think you may appreciate more of an open feeling of Fedora. I think Slackware, Arch and Gentoo are going to be a lot of non Ubuntu exposure. If you use a moderate Distro you can go either way with it. After using Mandriva for two years and then switching to Fedora , I think I'm somewhere in the middle right now. Mandriva did not hold your hand but had a helpful GUI to solve problems. Fedora's GUI is not that helpful but Redhat is the alpha distro which means a solution is usually not that foreign to anyone. BSD is a fork of Unix and OpenSuse is like sailing a luxury cruise liner to get a loaf of bread.